Finding the best undervalued centre-backs in La Liga – data analysis | OneFootball

The increasing use of data has altered team recruitment strategy as teams use it to discover undervalued talent in order to compete with other clubs who may have a greater budget. Here, we will analyse which centre-backs in La Liga are undervalued; the COVID-19 pandemic has restricted several sides’ budgets therefore signing undervalued talent is more important than ever to improve the team.

In La Liga, Eibar are a great example of signing undervalued players and have done brilliantly in bridging the gap between themselves and others in the league. They featured in the Financial Times as one of the fastest-growing companies in Europe in 2018 and 2019.

Undervalued is defined as the value below the real worth. In football terms, this is a player who has a market value less than their real value, meaning that if they were bought for their market value then the player’s new club will have signed an undervalued player.

Method and Assumptions

In this data analysis, assumptions about a club’s recruitment policy have been made to discover undervalued players:

-Centre-backs must be 30 years old or younger, therefore an investment for several seasons.

-Centre-backs were not on loan last season because it is unknown whether their parent club will wish to keep the player for this season and players from Real Mallorca, Leganés and Espanyol are all included.

-Centre-backs are not regular starters at one of Atlético Madrid, Real Madrid or Barcelona as all three will demand a high fee and we are looking at relatively low fee players.

-Centre-backs have played a minimum of 1000 minutes this season so that their statistics are a fair representation of their ability.

This filtered the centre-back data to 62 players. From this, the top 24 were chosen based on their standardised z-score defensive ranking which used player statistics from the first three performance tests.

It is assumed that the centre-backs will need to perform their defending duties well in order to be placed on the shortlist. Many clubs who sign undervalued centre-backs demand their centre-back to be a good defender as clubs with a restricted budget look to reduce the number of goals that they concede to bridge the gap between themselves and the bigger clubs.

Winning their battles

We will first analyse how strong each player is when they tackle. This performance test is important for many clubs when signing a centre-back because they need the player to win a large majority of their ground duels or risk their team conceding dangerous attacks. We can also understand how proactive the player is by being involved in more defensive duels when having to defend.

Joseph Aidoo performs brilliantly in defensive duels having won 78.19% while competing in 6.27 per 90. This is evidence of his strength in tackling and stopping attacks, and has aided Celta Vigo as they had to defend in large portions of their matches last season.

Young players Jules Koundé and Pau Torres rank as having the highest market value in this analysis, however, their age means that they could be bought for an undervalued value as they are likely to improve in the future. Both won over 75% of their defensive duels and played over 2500 minutes last season as they were both instrumental in their sides push for European places.

Sidnei and Nestor Araújo are currently nearing the end of their peak but have contested in 5.66 and 5.89 defensive duels per 90 respectively. This shows their strength in being proactive to predict the opposition threat and could also be an indication of their experience and aggressiveness by reading the opposition well to react, having won 73.48% and 83.4% of their defensive duels respectively.

Aerial ability

Next, we will look at each player’s aerial ability. It is important that each centre-back can win their aerial duels, especially in the Bundesliga where sides like to play long direct football or like to cross the ball as they attack the wings.

The best performer is David García who competed in the most aerial duels per 90 with an aerial duel per 90 success rate of 72.25%. He is nearing his peak as a 26-year-old and his aerial ability and age would suit Bundesliga sides that are looking to reduce the number of goals conceded from aerial crosses or long direct passes.

If a player competes in several aerial duels and wins a large percentage of their duels, we are confident that they are strong in contesting aerial battles. Artiz Elustondo won 62.18% of his aerial duels and competed in 6.63 aerial duels per 90 which is evidence of his bravery to challenge in the air and his strength when challenging.

Íñigo Martínez and Pedro Bigas should be noted given that they both competed in an above-average number of aerial duels per 90 and also won 65.17% and 66.09% of these duels respectively as they finish as the best performers behind Garcia.

Sidnei, Esteban Burgos and Kenneth Omeruo won a large percentage of their aerial duels however they competed in a below-average number of aerial duels, therefore, we cannot confidently conclude that they will be great additions for sides that need players who can deal with aerial threats. Burgos and Omerou play for Eibar and Leganés who contested in 55.56 and 47.35 aerial duels per 90 respectively, Burgos and Omerou’s positioning and bravery must be questioned as their sides contested in many aerial duels.

Reacting off the ball

This part of the analysis will analyse how reactive each centre-back is to the opposition shooting or passing. This will help understand each player’s defensive awareness and intelligence as they make these interceptions and blocks which can prevent key/through passes or goals.

The most outstanding performer here is Gabriel Paulista who made 6.73 interceptions per 90 and blocked 0.80 shots per 90. His defensive awareness to be able to read the game and quickly react to potential attacking danger helped Valencia concede 6.88 fewer goals than they should have, calculated from xG-G.

Erick Cabaco and Pedro Bigas rank above average on both metrics because Getafe and Eibar intensely press the opposition having allowed 6.60 and 8.16 passes per defensive action (PPDA) respectively. This style of play encourages the centre-backs to be reactive in intercepting passes in passing lanes and preventing shots as they intensely press the opposition. Cabaco is more impressive having made 5.96 interceptions per 90 and 0.85 shots blocked per 90.

Rúben Vezo, Martin Valjent, Rodrigo Ely and Pau Torres all perform well. Valjent was recently relegated with Real Mallorca and with a market value of £2 million, he would be a great undervalued signing as he is quick to react having made 5.66 interceptions per 90 and blocked 0.68 shots per 90.

The modern-day centre-back

We have looked at the centre-back’s defensive skills and now we will look at their technical skills when in possession of the ball. It is important for the centre-backs to maintain a high pass accuracy to reduce the risk of the opposition intercepting the pass and threatening the goal. Successful progressive passes are defined as passes that move the ball considerably forward and is effective to help the team transition quickly from defence to attack usually played by those in a ball-playing centre-back role. This metric is also analysed.

Jules Koundé and Pau Torres rank highly in this test. Both made 49.20 and 54.82 passes per 90 and had a pass accuracy of 90.78% and 87.24% respectively, both their teams like to make short passes in their defensive third.

Real Betis defenders Sidnei and Marc Bartra both made over 50 passes per 90 last season and were highly successful in completing over 85% of those passes. Real Betis controlled 56.50% ball possession last season, which is why both made so many passes.

It is worth noting Artiz Elustondo, Gabriel Paulista, Joseph Aidoo and Nestor Araújo in this analysis, all perform well having made over 40 passes per 90 and had a high percentage of successful passes. Elustondo performs particularly well having made 5.85 progressive passes per 90.

Íñigo Martínez’s Athletic Bilbao particularly like to play long forward passes as they averaged an average pass length of 21.37 which could be why he made 7.22 successful progressive passes per 90. His pass accuracy was below average at 82.11% and could be because he attempted more risky long passes to help his side transition quickly from defence to attack.

Limiting the errors

Finally, we will analyse which players are skilful enough to travel with the ball to aide their team’s defence to attack transition, another requirement for a ball-playing centre-back. Additionally, the percentage of offensive duels won will be analysed, a low success rate in offensive duels could mean that when the player has ball possession, they are at risk of being dispossessed.

Jules Koundé and Pedro Bigas perform relatively well having won 55.93% and 59.09% of their offensive duels and took part in at least one offensive duel per 90. If deemed necessary they could help their side attack as they are technically able to maintain possession of the ball, although they could still be a risk in possession as their offensive duels success rate was below 60%.

Unai Núñez and Leandro Cabrera perform well in keeping possession of the ball in an offensive duel having won 64.00% and 61.54% of their 1.33 and 1.06 offensive duels per 90 respectively. Nunez’s valuation of £16 million could be an undervaluation given he’s a 23-year-old and has the potential to play well in the ball-playing defender role.

Pau Torres, Nestor Araújo, Íñigo Martínez and Yeray Álvarez all made at least one progressive run per 90 and this is attractive for sides that like to control possession as their centre-backs can play as a deep-lying pivot at times if they drive forward when in possession of the ball.

Shortlist

In this data analysis, four players have been shortlisted. Each player’s market value differs to cover a wide variety of clubs. The graph below displays the performance metrics analysed in this piece and some percentages are changed to per 90 to understand more about the activity of each player meaning how much they do per 90. Some metrics have extremely low values, however, these are less important when comparing all four as their performance is similar in those metrics.

Pedro Bigas – Market value: £1 million:

After struggling to break into Eibar’s defence at the beginning of the season, Pedro Bigas was Eibar’s best defender, having won 66% of his aerial duels, made 5.82 interceptions per 90 and blocked 0.56 shots per 90. His defensive awareness and experience allow him to be proactive in occupying positions to prevent an opposition attack. Bigas looks a great undervalued signing for any club, only valued at £1 million. He scored three goals last season and fits Eibar’s transfer policy by signing undervalued talent.

Sidnei – Market value: £8 million:

The Brazilian turns 31 at the end of the month and his vast experience and knowledge in La Liga has allowed him to successfully win 73.49% of his ground duels per 90 and block 0.70 shots per 90 as he is proactive to predict the opposition attackers. Sidnei impressively made 55.60 passes per 90 while successfully making 91.46% of these passes. At a market value of £8 million, he could be a shrewd purchase for sides such as SD Huesca who play a short passing style, if deemed surplus to requirements by Manuel Pellegrini.

Joseph Aidoo – Market value: £6 million:

The 24-year-old has adjusted well to Spanish football having made 32 appearances last season after signing from KRC Gent. Celta Vigo finished 17th last season, this forced him into 10.74 defensive actions per 90 and his 78.19% tackle success rate is evidence of his strength in the tackle. He only won 53.33% of his aerial duels per 90, however, given his age he is likely to improve and £6 million is undervalued given that 23-year-old Pau Torres is valued at £30 million, yet Torres didn’t outperform Aidoo in this data analysis.

Jules Koundé – Market value: £30 million:

The Frenchman is valued a lot higher than the others shortlisted but the 21-year-old has a lot of potential. He improved a lot last season having made 29 appearances as Sevilla finished in the Champions League places. He excels in his individual battles having won 78% of his defensive duels and 61.59% of his aerial duels. He appears to fit the ball-playing defender role well having made 6.40 progressive passes per 90 and a pass accuracy of 90.78%. Manchester City are currently looking for a centre-back and Koundé could be a great investment for Guardiola’s side as he is likely to improve in the future and his strength in individual duels will help him perform well in the Premier League.

Final remarks

This data analysis has highlighted the best undervalued centre-backs in La Liga. It has been designed to cater for all sides so that no matter the budget or ambition of the club, there are a few players who could be scouted further to understand more about their ability and style. It is hard to determine some attributes such as positioning, concentration and composure, however, statistics can create the first impression about a player for clubs to determine whether they may scout some of the players further using video analysis.

From the data, 17 players who had a market value of less than £10 million were used in this analysis and is evidence that undervalued players can be discovered as they perform at a similar level to those whose market value is greater.